Sequential Read/Write Speed

To measure sequential performance I ran a 3 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. The results reported are in average MB/s over the entire test length.

This is pretty impressive. The new SF-2500 can write incompressible data sequentially at around the speed the SF-1200 could write highly compressible data. In other words, the Vertex 3 Pro at its slowest is as fast as the Vertex 2 is at its fastest. And that's just at 3Gbps.

The Vertex 3 Pro really shines when paired with a 6Gbps controller. At low queue depths you're looking at 381MB/s writes, from a single drive, with highly compressible data. Write incompressible data and you've still got the fastest SSD on the planet.

Micron is aiming for 260MB/s writes for the C400, which is independent of data type. If Micron can manage 260MB/s in sequential writes that will only give it a minor advantage over the worst case performance of the Vertex 3 Pro, and put it at a significant disadvantage compared to OCZ's best case.

Initially, SandForce appears to have significantly improved performance handling in the worst case of incompressible writes. While the old SF-1200 could only deliver 63% of its maximum performance when dealing with incompressible data, the SF-2500 holds on to 92% of it over a 3Gbps SATA interface. Remove the SATA bottleneck however and the performance difference returns to what we're used to. Over 6Gbps SATA the SF-2500 manages 63% of maximum performance if it's writing incompressible data.

Note that the peak 6Gbps sequential write figures jump up to around 500MB/s if you hit the drive with a heavier workload, which we'll see a bit later.

Sequential read performance continues to be dominated by OCZ and SandForce. Over a 3Gbps interface SandForce improved performance by 20 - 40%, but over a 6Gbps interface the jump is just huge. For incompressible data we're talking about nearly 400MB/s from a single drive. I don't believe you'd even be able to generate the workloads necessary to saturate a RAID-0 of two of these drives on a desktop system.

Fact: Most computers end their life with the same hardware they started with. Only a small DIY market actually upgrades their hard disk and migrates their OS/data. So what if 50% runs XP? 49% of those won't replace their HDD with an SSD anyway. They might get a new machine with an SSD though, and almost all new machines get Windows 7 now.Reply

Very interesting indeed....good article too. One has to wonder though - looking at what is currently happening with 25 nm NAND in vertex 2 drives, which have lower performance and reliability than their 34 nm brethren ánd are sold at the same price without any indication - how the normal Vertex 3 will fare...Hoping they'll be as good in that regard as the original vertex 2's, and I may well indeed jump on the SSD bandwagon this year :) Been holding off for lower price (and higher performance, if I can get it without a big price hike); I want 160 GB to be able to have all my games and OS on there.Reply

It is not the NAND it self having the issue but the numbers of the chips. You get same capacity with half the chips, so the controller has less opportunity to write in parallel.

This is the same reason why with Crucial's C300 the larger (256) drive is faster than the smaller (128).

Speed will drop for smaller drivers but if price goes down this will be counterbalanced by larger capacity faster drives.

The "if" is very questionable of course considering that OCZ replaced NAND on current Vertex2 with no price cut (not even a change in part number; you just discover you get a slower drive after you mount it)Reply

Except that there are already twice as many chips as there are channels (8 channels, 16 NAND chips - see pg 3 of the article), so halving the number of chips simply brings the channel to chip ratio down to 1:1, which is hardly a problem.It's when you have unused channels that things slow down.Reply